These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Anti-Climax Boss: In the Christmas special the man known as "Jesus" might be the most powerful foe the gang have faced. How is he defeated? He uses his psychic powers to pull a cabinet too hard and hits himself in the head. Hoist by His Own Petard. But hey, the gang still won.
Simon, particularly after the revelation that Future!Simon is Super-Hoodie
Fridge Brilliance: The existence of Psycho!Rudy makes sense when you take a long look at Rudy's behavior: he wet the bed into his late teens, suffers from stifling levels of social awkwardness, deeply suppresses his emotions and traumas, and over the course of the series has shown a distinct lack of empathy, at least when nothing directly effects him
Fridge Logic: In Series 1 Episode 2, Ruth produces a set of keys, giving the impression that she is a member of staff and has permission to be in the community centre after hours. As it turns out she is actually a client-there is no reason for her to have the keys or to be hanging around the community centre when it is closed.
Given that the place has the security of a wet paper bag, it's not too hard to imagine she stole them.
The show has quite a bit of this. Another example being when Nathan's brother kidnaps his dad, but was apparently dead the whole time, and supposedly only Nathan could see him. Or at least his dad never did.
Hilarious in Hindsight: In 2.5, when asked why he bothers to try and rescue Simon from danger, Nathan replies: "The little bastard gets under your skin, doesn't he?". A couple of years later, Iwan Rheon, the actor playing Simon, joined the cast of Game of Thrones as Ramsay Snow, Lord Bolton's bastard son who enjoys flaying people alive.
Ho Yay: Nathan and Simon. It starts off as Nathan essentially sexually harassing Simon for shock value, but as their friendship develops, Nathan's teasing seems to evolve into genuine affection.
And then there's the episode in which Nathan is mind-controlled into falling genuinely in love with Simon, much to the latter's bemusement, since Nathan's attentions go from obnoxious to sweet and gentle.
Season 3 brings us Rudy and his other self, what with the wrestling and talk of fucking himself.
The Season 5 premiere lampshades this, with Rudy Too's attempts to get Rudy One to join a superpower support group sounding like an effort to make him join couples therapy.
Abbey meets a girl at the bar, Laura, who's smell she recognises, making it one of her few memories. She sniffs her a few times, jokes about fucking her with a strap-on, then tells her she's the best smelling person ever.
Jerkass Woobie: Nathan, whose jerkassery is largely balanced out by the fact that the writers simply adore placing him in unpleasant situations (though he often has it coming). Essentially, the universe hates him so we don't have to.
Some Anvils Need to Be Dropped: The show takes pains to educate people on what can be considered rape. If you didn't get it when it was implied by Alisha's use of her powers, it was later explicitly called rape by Curtis. Then there was the coach drugging his athletes and even later a very clear explanation from Simon that having sex with someone who's asleep is rape. Finn also counsels against having sex with very drunk girls.
Happens with Alisha and Future!Simon. Their relationship is developed over the course of two episodes, Alisha only falls in love with him because he tells her she will, and because he's the only person that can touch her.
Squick: In 3.6 Rudy drops his ice cream upon discovering while urinating what his one night stand did to his nether regions.
Unintentionally Sympathetic: Many of the villains can be perceived as this, most of them were always down on their luck Butt Monkeys before they got their powers, such as Brian the "Milk Guy". He led an incredibly mundane life, then his powers made him famous, then when other people with better powers came along everyone started to ignore him again.
Then again, Howard Overman did state in an interview that he tried to avoid creating wholly "good" or "evil" characters, and tried to give all of the antagonists at least some logical motives for the way they behaved. So most of them were probably intended to be somewhat sympathetic.
Unintentionally Unsympathetic: Sally on-paper has reasons for her behaviour. She is worried about Tony (they were together) and she suspects something is going on. However the way she goes about finding this out takes away a lot of sympathy from her. Namely manipulating Simon - read: an emotionally vulnerable teenager with a crush on her - and borderline seducing him for information. And she also physically attacks him when she discovers the truth.
The Woobie: Painfully shy and lonely Simon endured years of bullying prior to the show, and still doesn't get off lightly mostly due to his and Nathan's personality clash.
Rudy's literal split personality has this in the introverted one, who admits that Rudy tried to kill himself after he lost his virginity to Alisha and she treated him badly.
Later on, his womanizing ways stop and genuinely falls in love with a sweet, innocent girl who dies.
Curtis loses his athletic career, his girlfriend dies, he gets himself pregnant, his next girlfriend uses him and tries to kill him, then finally he becomes a zombie and shoots himself to save the rest from infection.